Ignition and reactor application of deuterium based fuel cycles in field reversed configurations

Abstract

Self-consistent plasma modelling, on the assumption that all particle species have the same confinement time, is applied to a field reversed configuration (FRC) to show that plausible designs of an ignited advanced fuel reactor are possible within the framework of present day technology. FRCs in the ⟨β⟩ ∼ 1 state are predicted to be microscopically and macroscopically stable; here, any ignited state must be of this kind since the plasma is heated up by a vast amount of nuclear power which even exceeds the electric output. In the ⟨β⟩ ∼ 1 state, the steep pressure gradient appears to concentrate dissipation into a thin sheath formed on the plasma surface; hence, the problem can be solved independently of the detailed local dissipative properties, in analogy to the case of a supersonic flow decelerated through an Hugoniot adiabatic shock. It was found out that, in the ignited state, self-pinching of the electrons takes place in the scrape-off layer towards the X-point so that the size of the loss hole from the scrape-off layer is reduced, which raises the edge plasma pressure to a high level; thereby, serious impurity concentration is eliminated. In the paper, possible D-based steady state fuel cycles are studied systematically by using a formulation which predicts each important parameter of a simple toroidal FRC reactor if only the electric power output and the plasma radius are specified. In optimizing the burning temperature, care was taken to satisfy the criteria for thermal stability. A study has also been pursued on a complex closed reactor system which is fed by D alone and exhausts the final fusion products only. It is found that flexible design is possible for such a complex system to minimize construction cost or environmental effects. Advanced fuel reactors are demonstrated to be very compact in size so that a field strength and a plasma volume approximately equal to those of JT-60 may be sufficient for a fusion reactor constituting the basis of a 1000 MW(e) power plant